Preserving wood.



. ne wand useful Improvements in Preserv- WILLIAM B. CHISOLM, OF CHARLESTON, SOUTH CAROLINA.

955, No Drawing.

To all whom it may concern:

Be it ,known that LVILLIAM B. CrrIsoLM, a citizen of the United States, residin at Charleston,county of Charleston, and tate of South Carolina, --have invented certain ing'Wood and- I; do hereby declare the following to be afull; clear, and exactjdescription of theinvention, such as will enable others skilled in the'art to which itappertains to make-anduse the same.

The object of; ray-invention is to protect wood from that-attacks of veagetahle, fungoid and microbe-organisms an of destructive insects and auimalcula',.and the like, by impregnating it with an aqueous solution carrying;sulfunin, such a, form as to de osit free sulfur Within the pores of the wooc It is basedguppn'the discovery made by me that when wood is,, impregnated,with a hot-amp e tier ous solution 'oh'tamed hy boiling toge water, lime-and, sulfur, there is deposited free sulfur in and throughout the pores of the; wood and also combined sulfur, which latter, likewise deposited in thepores of the wood is itself gradually converted in part intofree, sulfur.

' that the hot solution has high capillary activity, enabling it to readily penetrate into the pores of the denser portions of the wood, so that the function of the deposit as a fun gicide and germicide is realized to corresponding advantage.

In the preferred practice of my invention, I prepare the solution to be employed for the impregnation of the wood by boiling in water a mixture of four parts, by weight, of.

sulfur (as, for instance, flowers of sulfur, or crushed or ground rock sulfur) and one 'part of lime (preferably unslaked calcic oxld). \Vhen the liquid attains a temperature,

of' about seventy degrees Fahrenheit, it takes on the color of a light orange red, and this color radually dee ens to an almost claret red during the oiling opera tion, which is'continued until that color is fully'attained. Thereupon the solution is separated from the residue, by means of siphoning, decantation or filtration, and the wood preferably immediately impregnated with the solution at about the boiling point; as I have found that if the temperature is emitted to notably fall some of the sulfur as a tendenc to separate out from it, which is undesira le for the reason that Specification of Letters Patent. .ApplieWlfile'd February 16, 1999 Serial No. 475,237.

ably impregn I have also ascertalned' PRESERVING WOOD.

the purposes ofthe invention are best subserved by permitting the solution to carry with it into the pores of the wood as large a proportion of sulfur as it will. retain or carry. Moreover I have discovered that this tendency of some of'the sulfur to separate out from the solution when the temper ature is lowered can be turned to particular advantage in the. practice of my invention, for the reason that as the wood is preferated with the solution at or near the bollingjpoint, it: will follow that when the wood so impregnated is removed from the treating vessels; andpermitted to cool, free sulfur; will be deposited, from the solution and into the open pores and vesicles of. the. wood, impregnating themvwith solid matter (sulfur and compounds of Patented Apr. 19,1910. Q

lime) which, toa great extent, prevents the possibility'of 'decay jt being well known and more porous portions... The impregnation of the wood may be performed by any of the usual methods, such as those employing vacuum or pressure. I have also found that to a large extent, decayv in the.wood treated can be prevented by merely impregnating the sap portions and the more porous portions with the solution, even when the heart portions are not fully impregnated. For certain classes of work this will be found a sufficient treatment and I- therefore do not desire to limit myself, in the practice 'of the invention to the thorough impregnation of all portions of the wood, heart-as well as sap. In fact, the sap portion of wood is much more inclined to rot than the heart portion and is much more porous,

that decay "commences'in these openivesicles' is almost impossible for any of the deleo terious organisms to initiate decay.

The relative ro ortions of the firmly combined sulfur Ice cium sulfid) and of the sulfur otherwise present in the solution-will vary in accordance with its the higher the temperature, the greater the ca acity of the solution to carry additional su fur, so that at or near the boiling point this carrying capacity is at its maximum.

In some instances,

temperature,- 106 instead of lime, I may no employ with the rock sulfur or flowers of sulfur of the original mixture, a suitable solution' appropriate for the main purposes of my invention; but, in most cases, I prefer to employ lime as the alkali for producing the sulfur solution, on account of its cheapness and convenience, and because the calcium salts in themselves have preservative effects and are less inclined to deliquesc'e than the corresponding compounds of sodium, potassium or ammonium.

To prevent the leaching out of the impregnated sulfur from the surface 'of the wood treated, in those instances where it is employed under water, (gas, for instance, in the construction of woo en piers, piles and the like), I prefer, after impregnating the wood tothe extent desired with the aqueous solution of combined and'uncombined sulfur, to then give it a surface coating produced by bringing to fusion a mixture of unslaked lime and sulfur in substantially the proportions, by weight, of one part of lime to four parts of sulfur according to the precess of my Patent No. 802,680, thereby hardening the lumber and filling its surface pores and preventing the leaching out of any of the soluble sulfurwith which the wood has been impregnated and thereby absolutely preventing any attack whatever upon the wood by the teredo worm, white ants, or any of the low animal organisms.

In another and co-pending application Serial No. 513,039, filed August 16, 1909, I have described and claimed a modified process wherein an excess of alkali is employed, this excess of alkali being sufficient to produce chemical changes in some of the wood constituents.

Having thus described my invention, what I claim is 1. The method of treating wood which consists inimpregnating its pores with an aqueous solution carrying an excess of dis solved sulfur in such a form as'to dep'osit finely divided free sulfur within the pores. 2. The method of treating wood which consists in inipregnating its POIBS-Wltll an aqueous solution, contaimng sulfur in such form as to be at once deposited as such within the pores of the wood, and also containing combined sulfur in such a condition that after the impregnation of the pores of the wood it will be gradually converted in part into finely divided free sulfur. I

3. The method of treating wood which consists in impregnating it with a hot solution of a calcium sulfid, said solution carry ing sufficient additional sulfur to cause its color to be a clear claret red.

4:. The method 'of treating wood which consists in impregnatin it with a hot solution of a calcium sulfi said solution containing suflicient additional sulfur to cause its color to be a clear claret red, such impregnation being carried on at substantially a boiling temperature.

5; As a'new article of manufacture, wood impregnated with an alkaline sulfid and also carrying intimately distributed particles of free sulfur in the pores of its mass.

6. As a new article of manufacture, wood impregnated with a calcium sulfid and also free sulfur in the pores of its mass.

In testlmony whereof I affix my slgnature, in presence of two witnesses.

lVILLIAh/I B. CI IISOLM. Witnesses: I

CHAS. S. BRYAN, JOHN C. PENNIE.

carrying intimately distributed particles'of 

